A former FEMA worker who beat his elderly mother with her own cane, also smothered her with a pillow – and now the 94-year-old is expected to die, Brooklyn prosecutors said Tuesday.

Mark Farrell, 64, was arrested Monday for allegedly attacking his mother, Dorothy, as she slept on a couch inside his Marine Park home, law enforcement sources said.

“The defendant repeatedly struck his 94-year-old mother with a cane,” said Brooklyn prosecutor Wilfredo Cotto. “[Dorothy] is currently in critical condition and is likely to die … there are also allegations the defendant smothered [Dorothy] with a pillow.”

The unhinged former federal worker claimed his mom wanted to die and he was just trying to assist her with her wish when he attacked her as she slept on a couch, law enforcement sources said.

Farrell sported a bright white beard and wore a white jumpsuit and no shoes at his brief Brooklyn criminal court appearance.

“I have to find my clothes,” Farrell said confusedly to his attorney as he was led out of court.

“The pictures are just awful. There was blood everywhere,” a law-enforcement source said of the crime scene.

“Dorothy Farrell was bleeding from multiple lacerations to her hands, face, and head, and that next to her was a bloody cane and pillow,” the criminal complaint states.

Farrell moved his mom into his home after his dad died last year and used his FEMA pension to hire nurses to care for her, defense attorney Cary London said.

“He takes care of his mother, Dorothy, who he also loves,” London said, adding that Farrell was a varsity swimmer and in the drama club at Nazareth Regional High School in East Flatbush and worked as a FEMA disaster management specialist for 22 years.

A FEMA spokesman would not confirm Farrell had worked for the agency, citing federal privacy laws.

Farrell was charged with attempted murder and assault, but charges will likely be upgraded to murder if his mother — who is in critical condition at Kings County Hospital — dies.